NUR1016 Lecture 4 (Treatment and prevention of infections) 2024/2025 Tung Wah College PDF

Tung Wah College NUR1016 AY2024/2025 Semester 2 Microbiology and Pharmacology Microbiology Lecture (L04) Treatment & Prevention of Infections Sony SO Jan 2025 (1) Treatment & (2) Prevention of Infections Glossary o Bacteriostatic - suffix “statis” – slowing; a substance cause a reversible inhi...

Tung Wah College NUR1016 AY2024/2025 Semester 2 Microbiology and Pharmacology Microbiology Lecture (L04) Treatment & Prevention of Infections Sony SO Jan 2025 (1) Treatment & (2) Prevention of Infections Glossary o Bacteriostatic - suffix “statis” – slowing; a substance cause a reversible inhibition of growth, with bacterial growth restarting after elimination of the drug; Bacteriostatic antimicrobial. o Bactericide - suffix “icide” - the act of killing; a substance that kills bacteria. o Antimicrobial Agents - including antibiotics, antivirals, antifungals and antiparasitics - are medicines used to prevent and treat infections in humans, animals and plants o Antimicrobial Resistance (AMR) - occurs when bacteria, viruses, fungi and parasites no longer respond to antimicrobial medicines. As a result of drug resistance, antibiotics and other antimicrobial medicines become ineffective and infections become difficult or impossible to treat, increasing the risk of disease spread, severe illness, disability and death. o Antibiotics - are drugs/medicines for treating bacterial infections, either by killing the bacteria or stopping them from growing. o Spectrum of Activity narrow-spectrum antimicrobial - targets only specific subsets of bacterial pathogens. broad-spectrum antimicrobial - targets a wide variety of bacterial pathogens, including both gram-positive and gram-negative species (CHP, 2023) Mechanisms Of Drug Action On Bacterial Cells (1 of 3) (Pharmacology Department Tulane University, 2016) Mechanisms Of Drug Action On Bacterial Cells (3 of 3) Inhibitors of cell wall synthesis o Bacterial cells are surrounded by cell walls made of peptidoglycan. Peptidoglycan biosynthesis is essential to the integrity of the cell wall structure, and it is the outermost layer and the main component of the cell wall. Specific antibiotics interfere with the biosynthesis of peptidoglycans, thereby destroying the integrity of the cell wall o beta-lactam antibiotics (penicillins and cephalosporins), bacitracin and vancomycin, interrupt specific points in the synthesis pathway for bacterial cell walls and therefore inhibit cell wall production Inhibitors of protein synthesis o Protein synthesis is a complex, multi-step process involving many enzymes and conformational alignment. o Several types of antibacterial agents—streptogramins, chloramphenicol, and tetracyclines—target bacterial protein synthesis by binding to either the 30S or 50S subunits of bacterial ribosomes. These drugs usually arrest bacterial growth. This means they have a “bacteriostatic” effect. o In the case of aminoglycosides, binding to the 30S ribosome produces incorrectly-formed proteins, resulting in bacterial death. This is a “bactericidal” effect. (Creative Biolabs, n.d.; Pharmacology Department Tulane University, 2016) Mechanisms Of Drug Action On Bacterial Cells (2 of 3) Inhibitors of cell membrane o Cell membranes segregate and regulate the intra- and extracellular flow of vital substances, and damage to this important barrier could result in leakage of important solutes essential for the cell’s survival. o Because cell membranes are a feature of both prokaryotic and eukaryotic cells, drugs of this class are often poorly selective and could be toxic to the host if they gain access to the host’s bloodstream. o Drugs that act through this mechanism, such as polymyxin B and colistin, are used to treat topical infections or, if poorly absorbed after oral administration, infections in the gastrointestinal tract. Inhibitors of nucleic acid (DNA and RNA) Synthesis o DNA and RNA are the keys to the replication of all living forms, including bacteria. Some antimicrobial drugs work by binding and inhibiting molecules involved in DNA coiling or transcription to RNA, ultimately compromising bacterial multiplication and survival. o Examples include drugs like the fluoroquinolones, metronidazole (Flagyl), and rifampin Inhibitors of Metabolic Pathways o Bacterial metabolism inhibitors are a class of antibiotics that target nucleic acid and amino acid synthesis pathways. o sulfonamides and trimethoprim disrupt the folic acid pathway, which is necessary for the production of nucleic acids, the precursors of DNA and RNA. (Creative Biolabs, n.d.; Pharmacology Department Tulane University, 2016)  Reproduction of Virus – Viral replication SARS-CoV-2 cell lysis Budding (Oiseth et al., 2020) Antiviral Drugs Mechanisms of Action, Animation https://www.youtube.com/watch?v=IOXEAAHmzT4 (Alila Medical Media, 2020) Antimicrobial Resistance (AMR)  Multi-Drug Resistant Organisms (MDROs) 多重抗藥性微生物 MDROs refer to those microorganisms that cause infections not treatable by several classes of commonly used antimicrobials Methicillin-Resistant Staphylococcus aureus (MRSA) 耐甲氧西林金黃葡萄球菌（一般稱為耐藥性金 黃葡萄球菌） Vancomycin-Intermediate / Resistant Staphylococcus aureus 萬古霉素中介耐藥性金黃葡萄 球菌 / 耐萬古霉素金黃葡萄球菌 (VISA / VRSA) Vancomycin-Resistant Enterococcus (VRE) 耐萬古霉素腸球菌 Carbapenemase-Producing Enterobacteriaceae (CPE) 產碳青霉烯酶腸道桿菌 Carbapenem-Resistant Acinetobacter (CRA) 耐碳青霉烯鮑氏不動桿菌 Multi-Drug Resistant Pseudomonas aeruginosa (MRPA) 耐多藥綠膿假單胞菌 Multi-Drug Resistant Acinetobacter (MDRA) 耐多藥鮑氏不動桿菌 Candida auri 耳念珠菌 Candida auris (C. auris) is an emerging multidrug-resistant fungus (CHP, 2023)  Causes of Antimicrobial (Drug) Resistance (1 of 4) Selective Pressure Mutation In the presence of an antimicrobial, microbes are Most microbes reproduce by dividing every few hours, allowing either killed or, if they carry resistance genes, them to evolve rapidly and adapt quickly to new environmental survive. These survivors will replicate, and their conditions. During replication, mutations arise and some of progeny will quickly become the dominant type these mutations may help an individual microbe survive throughout the microbial population. exposure to an antimicrobial. (Haavisto, 2023; NIAID, 2011) Causes of Antimicrobial (Drug) Resistance (2 of 4) Horizontal Gene Transfer o One of the main vehicles for gene transfer among bacteria are small circular pieces of DNA, or plasmids. o Plasmids can be transferred through direct physical contact between bacteria in a process known as conjugation, which helps bacteria share their antibiotic resistance genes with their neighbors.. Transfer of a plasmid (green loop) between two ba cterial cells through the process of conjugation. Source: Getting et al./Microbiology Spectrum, Jan. 2018 (Haavisto, 2023; NIAID, 2011) Causes of Antimicrobial (Drug) Resistance (3 of 4) Societal Pressures - Use of antimicrobials, even when used appropriately, creates a selective pressure for resistant organisms. However, there are additional societal pressures that act to accelerate the increase of antimicrobial resistance. Inappropriate Use - Sometimes healthcare providers will prescribe antimicrobials inappropriately, wishing to placate an insistent patient who has a viral infection or an as-yet undiagnosed condition. However, such process would exacerbate the selection of resistant microorganisms process as well. Inadequate Diagnostics - More often, healthcare providers must use incomplete or imperfect information to diagnose an infection and thus prescribe an antimicrobial just-in-case or prescribe a broad-spectrum antimicrobial when a specific antibiotic might be better. These situations contribute to selective pressure and accelerate antimicrobial resistance. (NIAID, 2011) Causes of Antimicrobial (Drug) Resistance (4 of 4) Hospital Use - Critically ill patients are more susceptible to infections and, thus, often require the aid of antimicrobials. However, the heavier use of antimicrobials in these patients can worsen the problem by selecting for antimicrobial-resistant microorganisms. The extensive use of antimicrobials and close contact among sick patients creates a fertile environment for the spread of antimicrobial-resistant germs. Agricultural Use - Scientists also believe that the practice of adding antibiotics to agricultural feed promotes drug resistance. More than half of the antibiotics produced in the United States are used for agricultural purposes. However, there is still much debate about whether drug-resistant microbes in animals pose a significant public health burden. (NIAID, 2011)  Mobile Genetic Elements How Antibiotic Resistance Moves Directly Germ to Germ Resistance traits can be inherited generation to generation. They can also pass directly from germ to germ by way of mobile genetic elements. (US CDC, n.d.) How Bacteria and Fungi Fight Back Against Antibiotics Antibiotics fight germs (bacteria and fungi). But germs fight back and find new ways to survive. Their defense strategies are called resistance mechanisms Germs change or destroy the antibiotics with enzymes, proteins that break down the drug Germs develop new cell processes that avoid using the antibiotic’s target. Germs change the antibiotic’s target so the drug can no longer fit and do its job Germs restrict access Germs get rid of by changing the antibiotics using pumps. entryways or limiting the number of entryway (CDC US, 2024) Antimicrobial Resistance Mechanisms Resistance Mechanisms Description Restrict access of the Germs restrict access by changing the entryways or limiting the number of antibiotic entryways. Get rid of the antibiotic Germs get rid of antibiotics using pumps in their cell walls to remove or antifungal antibiotic drugs that enter the cell. Change or destroy the Germs change or destroy the antibiotics with enzymes, proteins that break antibiotic down the drug. Change the targets for Many antibiotic drugs are designed to single out and destroy specific parts the antibiotic or (or targets) of a bacterium. Germs change the antibiotic’s target so the antifungal drug can no longer fit and do its job. Bypass the effects of Germs develop new cell processes that avoid using the antibiotic’s target. the antibiotic (CDC US, 2024) Medical Suffix– “ase” What is medical suffix – “ase”? o “ase” is used in biochemistry to form names of enzymes. o Beta-Lactamases - Beta-lactamases are a diverse class of enzymes produced by bacteria that break open the beta-lactam ring, inactivating the beta-lactam (β-Lactam) antibiotic. What are Beta-lactam (β-Lactam) antibiotics? o antibiotics contain of four-membered lactam ring, designed as inhibitors of bacterial cell wall synthesis o four groups of antibiotics belong to beta-lactam family - penicillins, cephalosporin, carbapenem, and monobactam. penicillin cephalosporin monobactam carbapenem (CDC US, 2016) Penicillins, Cephalosporin, Carbapenem, And Monobactam Cephalosporin include the following: o First generation - cephalexin and cefazolin o Second generation - cefaclor, cefuroxime and cefoxitin. o Third generation – Ceftriaxone Carbapenems include the following: o Ertapenem o Imipenem o Meropenem o Tebipenem monobactam o Aztreonam (Ikram, n.d.) Ideal Antimicrobial Agents o Microbicidal rather than microbistatic o Relatively soluble; functions even when highly diluted in body fluids o Remains potent long enough to act and is not broken down or excreted prematurely o Does not lead to induce antimicrobial resistance o Complements or assists the activities of the host’s defenses o Remain active in tissue and body fluids ie long half-life o Readily delivered to the site of infection o Reasonably price o Does not disrupt host’s health by causing allergy or predisposing the host to other infections  Multi-Drug Resistant Organisms (MDROs) 多重抗藥性微生物 MDROs refer to those microorganisms that cause infections not treatable by several classes of commonly used antimicrobials Methicillin-Resistant Staphylococcus aureus (MRSA) 耐甲氧西林金黃葡萄球菌（一般稱為耐藥性金 黃葡萄球菌） Vancomycin-Intermediate / Resistant Staphylococcus aureus 萬古霉素中介耐藥性金黃葡萄 球菌 / 耐萬古霉素金黃葡萄球菌 (VISA / VRSA) Vancomycin-Resistant Enterococcus (VRE) 耐萬古霉素腸球菌 Carbapenemase-Producing Enterobacteriaceae (CPE) 產碳青霉烯酶腸道桿菌 Carbapenem-Resistant Acinetobacter (CRA) 耐碳青霉烯鮑氏不動桿菌 Multi-Drug Resistant Pseudomonas aeruginosa (MRPA) 耐多藥綠膿假單胞菌 Multi-Drug Resistant Acinetobacter (MDRA) 耐多藥鮑氏不動桿菌 Candida auri 耳念珠菌 Candida auris (C. auris) is an emerging multidrug-resistant fungus (CHP, 2023) Methicillin-resistant Staphylococcus Aureus (MRSA) Infection o Hospital-associated MRSA (HA-MRSA) infection HA-MRSA are associated with nosocomial infections e.g. endocarditis and resistant to penicillins (including methicillin, oxacillin, cloxacillin), cephalosporins (except ceftaroline and ceftobiprole) and carbapenems o Community-associated MRSA (CA-MRSA) Infection Infections with S. aureus can also occur in community individuals who have not been hospitalised, stayed in residential care homes, or received medical procedures within a year prior to symptom onset. These are known as CA-MRSA infections. CA-MRSA predominately causes Simple (uncomplicated) skin and soft tissue infections such as folliculitis, furuncle, cellulitis (~90%), CA-MRSA strains often produce the leukotoxin Panton-Valentine Leucocidin (PVL), which is encoded by the two genes lukS-PV and lukF-PV. In contrast, only about 5% of methicillin sensitive strains of S. aureus (MSSA) and HA-MRSA carry the PVL genes. Multi-Drug Resistant Organisms (MDROs) (1 of 2) o What is Carbapenem-Resistant Enterobacteriaceae (CRE)? - In 2009, the CDC released a report on KPC-producing bacteria in which the term Carbapenem-Resistant Enterobacteriaceae (CRE) was proposed as more accurate, given the understanding that multiple species of Gram-negative bacteria can harbor the KPC-resistant element o What is Vancomycin-Resistant Enterococcus (VRE)? - a type of bacteria present in the gastrointestinal tract that develop resistance to many antibiotics, especially vancomycin o What is ESBL-producing Enterobacteriaceae? - Extended-spectrum β-lactamase (ESBL)- producing Enterobacteriaceae 「超廣譜乙內酰胺酶(ESBL)耐藥腸桿菌科細 菌」; Enterobacterales include germs like Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). ESBL-producing Enterobacterales infections are resistant to many prescribed antibiotics, such as penicillins and cephalosporins Multi-Drug Resistant Organisms (MDROs) (2 of 2) o Multiple-drugs Resistant Acinetobacter species (MDRA) - MDRA refers to Acinetobacter species that have been tested and found resistant to all antibiotics in the classes of Cephalosporins (exclude Cefiderocol), Fluoroquinolones, Aminoglycosides, Beta-lactam and Beta-lactamase inhibitor combinations and Carbapenems. o Multi-drug Resistant Pseudomonas aeruginosa (MRPA) - MRPA refers to a Pseudomonas aeruginosa isolate that is tested resistant to all antibiotics under the classes of Cephalosporins (Cefepime/ Ceftazidime), Fluoroquinolones (Ciprofloxacin/ Levofloxacin), Aminoglycosides (Gentamicin/ Amikacin), Beta-lactam with/without beta-lactamase inhibitor (Piperacillin/ Piperacillin-tazobactam/ Cefoperazone-sulbactam/ Ticarcillin-clavulanic acid) and Carbapenems (Imipenem/ Meropenem). (1) Treatment & (2) Prevention of Infections Drug Suffixes - Antibiotic, Antiviral, Antifungal Antibiotic o Tetracyclines: suffix - cycline, such as tetracycline, doxycycline. o Aminoglycosides : suffix - mycin, such as neomycin, gentamicin, streptomycin o Fluoroquinolones : suffix - floxacin, such as ciprofloxacin, levofloxacin. Antiviral o suffix –vir, such as acyclovir, ganciclovir, oseltamivir Antifungal o suffix – azole, such as clotrimazole, miconazole, econazole, and ketoconazole (Denali Rx, 2021) What Is The Difference Between Empirical & Prophylactic Antibiotic Treatment? o Prophylaxis Antibiotic (Antibiotic Cover) is the use of antibiotics (usually) BEFORE surgery, to prevent a bacterial infection. In general, the administration of an initial dose should be given within 30 minutes BEFORE surgical incision (coinciding with the induction of anaesthesia) to achieve an adequate tissue concentration at the time of initial incision. Administer additional intraoperative doses if the operation time exceeds two serum half-lives of the antimicrobial agent, or massive intraoperative blood losses occur The duration of antimicrobial prophylaxis should not routinely exceed 24 hours. o Empiric Antibiotic Therapy is often given to patients who have an unidentified proven or suspected infection. The responsible organism(s) or bacteria have not yet been confirmed, but treatment is required (Bassetti et al., 2000; SCIC & ICB, 2009)  Occupational Exposure – Post-Exposure Prophylaxis (PEP) Timely assessment and treatment First Aid are keys to success of PEP Sharps Injury 18% - o wound should be washed immediately and thoroughly with soap and water. 30%* 1.8% o Antiseptics are NOT necessary as there is no evidence of their efficacy. o Wounds should NOT be sucked. mucosal contact o such as spillage into the conjunctivae o the exposed part should also be washed immediately and liberally with clean running water HCV 0.3%- o Currently, there is NO effective vaccine or chemoprophylactic agent for preventing HCV 0.9% infection after accidental occupational exposure. o However, treatment of acute infection (interferon or pegylated interferon, with or without ribavirin) may prevent progression to chronic HCV infection * HBeAg carry the highest risk of infection at 37-62% (SCAS & ICB, 2014) Post-Exposure Prophylaxis (PEP) for HIV Not RELATED TO Occupational Exposure o Post-Exposure Prophylaxis (PEP) is a daily dose of anti-HIV medications, taken for 4 weeks that can potentially stop HIV infection after exposure. o PEP must be taken as soon as possible within 72 hours of someone being exposed. (AIDS Concern, 2021) How To Select Appropriate Antibiotic Before Releasing Culture With Sensitivity Test (C&ST) Report? https://www.chp.gov.hk/files/pdf/reducing_bacterial_resistance_with_impact.pdf (HO & WU, 2017) Community Acquired Methicillin Resistant Staphylococcus aureus (CA-MRSA) infection History o 45 years old man, Good past health o Right abdominal wall abscess for one week o Treated with oral ampicillin and cloxacillin o No improvement with antibiotics o Increasing pain, pustular discharge noted from abscess o Incision and drainage of abscess performed at A&E o Continued on oral ampicillin and cloxacillin o Culture revealed Staphylococcus aureus (methicillin resistant), Diagnosed as CA-MRSA infection o PCR positive for Panton-Valentine leucocidin (PVL) o Admitted and given one week of intravenous vancomycin o Subsequent history revealed recent body massage in China (? Source of CA-MRSA) (HKU The School of Clinical Medicine; 2014) Empiric antibiotic therapy is often given to patients who have an unidentified proven or suspected infection. The responsible organism(s) or bacteria have not yet been confirmed, but treatment is required. For simple SSTIs, initial antibiotic choice is empirical. Empiric antibiotic therapy methicillin sensitive beta-haemolytic Remark S.aureus streptococci Cloxacillin Good Some / Flucloxacillin Good Some / Amoxicillin Good NO / Amoxicillin - clavulanate Good Good Some clav·​u·​la·​nate (Augmentin) Cephalexin Good Good For penicillin-allergic patients except those with immediate (anaphylactic) hypersensitivity reactions Levofloxacin Some Some Good activity against some aerobic gram negative bacilli (CHP, 2017) 青霉素類 Penicillins 頭孢菌素類 Cephalosporins (例如: 阿莫西林 Amoxicillin) (例如: 頭孢氨芐Cephalexin Augmentin - contains Cephalexin - a beta-lactam antibiotic that two drugs: belongs to the 1st generation cephalosporin class (1) amoxicillin and (2) clavulanic acid Superinfection o A superinfection develops when the antibacterial intended for the preexisting infection kills the protective microbiota, allowing another pathogen resistant to the antibacterial to proliferate and cause a secondary infection o Common examples of superinfections that develop as a result of antimicrobial usage include yeast infections (candidiasis) and pseudomembranous colitis caused by Clostridioides difficile [Clostridium difficile] (The LibreTexts libraries, 2024) Antiprotozoal Drugs Classified into two main groups o Antimalarial drugs eg mefloquine, chloroquine, proguanil with atovaquone and doxycycline. They kill or inhibit the growth of protozoa by affecting different stage of the parasitic life cycle. They are used both to treat and prevent malaria. o Miscellaneous antiprotozoals Metronidazole is the most common treatment for trichomoniasis and giardiasis. Its action in the treatment of protozoal infections remains poorly understood, however, it may work by damaging protozoal DNA (Drug Office, 2013) Anthelmintics Drugs o Anthelmintics are medications used to eradicate parasitic worms (helminthes) from the human body. o Commonly used ones are mebendazole and its analogues flubendazole, piperazine, praziquantel and pyrantel. Others such as levamisole and pyrvinium have previously been used but not common any more. o Mebendazole, flubendazole, piperazine and pyrantel are indicated for roundworm infections. Mebendazole and flubendazole work by stopping the roundworms from using glucose and without it, the cells of the roundworms lose their energy supply and quickly die. Whereas, piperazine and pyrantel work by paralyzing the worms and causing the worms to "lose its grip" on the intestinal wall and be passed out of the system by natural process o Praziquantel is indicated for both tapeworm infections and fluke infections. It works by causing severe spasms and paralysis of the worms’ muscles (Drug Office, 2013) Local Immunization History  Elimination of Local Smallpox in 1979 華痘局於1910年正式啟用，並在卑路乍街 與域多利道的交界立一拱門，其紀念石匾 香港醫學博物館于1996年成立， 上 刻 有 ： 「TUNG WAH SMALLPOX HOSPITAL, A.D. 1910」的 英 文 字 樣 。 東 華 痘 局 當 時 主 要 前身是一所「細菌學檢驗所」， 以中醫藥治理天花病人以及接種牛痘。隨 後來易名為「病理檢驗所」檢驗 著天花絕跡，東華痘局於1938年交還政府 所自1906年啓用至70年代止，為 用作傳染病醫院，至香港重光後被拆卸。 全港市民提供足夠的牛痘疫苗， 拱門及奠基石被移放於附近西寧街的堅尼 讓市民預防天花病毒。 地城巴士總站現址 (Lee, 2013)  Elimination of Local Leprosy (麻風病) In Mid 1980' Photo 1 - 1950s, the number of confirmed leprosy cases in the territory increased. Sseverely affected cases were isolated in a leprosarium on Hei Ling Chaun 喜 靈 洲 till 1975. Photo 2 - 1975 -2000, leprosy cases Photo 1 were care Lai Chi Kok Hospital 荔枝 Photo 2 角醫院 o Hansen’s disease (also known as leprosy) is an infection caused by slow-growing bacteria called Mycobacterium leprae and Mycobacterium lepromatosis. o Hansen’s disease can be transmitted by droplets or via contact. However, the disease does not spread easily via social contact. Prolonged, close contact (e.g. household) over months with someone with untreated leprosy is needed to catch the disease o Leprosy is a curable disease; three drugs: dapsone, rifampicin and clofazimine as multi-drug therapy (MDT). o As per data of 2019, Brazil, India and Indonesia reported more than 10 000 new cases Image source: https://www.wetoasthk.com/laichikokhospital/ (Lau, 2002) Elimination of Local Polio (小 兒 麻 痺 症 ) in 2020 衛生署署長陳馮富珍醫生今日（十月三十日）表示，世界衛生組織「世衛」宣布在包 括香港的西太平洋地區，小兒麻痺已絕迹，香港因此引以為榮。陳馮富珍醫生在「消滅 脊髓灰質炎（小兒麻痺）野株病毒西太平洋地區委員會」於日本京都舉行的會議後，發表以上說 話。該會議宣布本土性小兒麻痺已在「世衛」西太平洋區包括香港的三十七個國家和地區絕迹。 陳醫生說，該疾病得以成功消滅，有賴於父母、公共和私家醫護人員的共同努力，以及「世衛」 和其他夥伴機構的技術支持。 她說：「小兒麻痺曾經是一個公共衛生問題。它在五十年代及六十年代引致顯著的病 發和死亡。但隨着口服小兒麻痺疫苗於一九六三年引入，有關個案數字急劇下跌。 」 「最後一宗本土性小兒麻痺個案於一九八三年呈報，最後 一宗疫苗感染小兒麻痺個案則於一九九五年發生。」… Vaccine Hesitancy (疫苗猶豫)  Mumps, Measles, & Rubella (MMR) cause Autism Spectrum Disorder (ASD/Autism)自閉症 Wakefield's study - Myths o Fallacy of affirming the consequent 「肯 定後項的謬誤」 - “If B follows A, then A is probably the cause of B” o In 1998, physician Andrew Wakefield published a study in a journal called The o MMR vaccine is administered to 12- to Lancet. The Lancet later retracted the study. 18-month-old children (HK 12 month, first o In an interview, the journal's 3 editor dosage). At this age, the first signs of an explained, "it was utterly clear, without impending developmental condition, such any ambiguity at all, that the statements as autism, start creeping in and become in the paper were utterly false." noticeable. The idea that “vaccine o Wakefield lost his license to practice medicine precedes event, hence vaccine causes in his home country, the U.K. Since then, no disease” fits the cognitive bias. one - not even Wakefield - has been able to replicate the results of his study. (Davidson, 2017)  Vaccines Safety Myths of using Mercury Compound- Ethyl-mercury o Vaccine Ingredients - thimerosal, a combination Mercury exists in three forms, namely metallic, consists of ethyl-mercury; use as preservatives prevent inorganic and organic. microbial growth concern for environmental contamination of Ethyl-mercury is an organomercurial that should be mercury accumulates in the food chain and in the distinguished from methylmercury human body is related to a different mercury compound called methyl mercury Dental amalgam contains various metals such as silver, copper and tin, as well as mercury. When Before 2005, thiomersal was present in diphtheria- mercury is combined with these metals, it becomes and tetanus-containing vaccines, as well as hepatitis an inactive stable substance ie inorganic mercury. B vaccine and some flu vaccines. World Health Organization (WHO) and other international health agents have both stated that there is no evidence of risk from thimerosal in vaccines (OHPD, 2023; RAS, 2017; US FDA, 2018) Vaccines safety - Use of Adjuvants (佐劑) o Adjuvants have been used safely in vaccines for decades. o An adjuvant is an ingredient used in some vaccines that helps create a stronger immune response in people receiving the vaccine, including the following - Aluminum salts MF59 Oil in water emulsion composed of squalene o Aluminum salts Many vaccines contain aluminium salts such as aluminium hydroxide, aluminium phosphate or potassium aluminium sulphate. Aluminium salts appear to slow down the release of the active ingredient from the vaccine once it is injected, and stimulate the immune system to respond to the vaccine. Aluminium is not used by the body. Any aluminium absorbed from food or other sources is gradually eliminated through the kidneys. o MF59 is an oil-in-water emulsion composed of squalene, which is a naturally occurring oil found in many plant and animal cells, as well as in humans (CDC US, 2024; The Vaccine Knowledge Project, 2022) Guillain-Barré syndrome (GBS) 吉巴氏綜合症 o GBS is a rare condition in which a person’s immune system attacks the peripheral nerves. o Infection with the bacteria Campylobacter jejuni, which causes gastroenteritis, is one of the most common risk factors for GBS o The first symptoms of GBS include weakness or tingling sensations. They usually start in the legs and can spread to the arms and face. o GBS is a true side effect of influenza vaccine, the estimated risk of one to two cases per million vaccinated is less than that for severe influenza. o In Hong Kong, between 42 and 65 cases of GBS are recorded each year from 2000 to 2024, irrespective of vaccination history, with more cases occurring during winter period. o Most people recover fully from even the most severe cases of Guillain-Barré syndrome. (CCIDER, 2010; WHO, 2023) Vaccine Side Effects o When not to get vaccinated o allergy to any of the active substances or ingredients in the vaccine o contraindications for some vaccines. For example, people with immune system disorders, may not be able to receive certain vaccines, such as measles, mumps, rubella, varicella, or oral typhoid o some vaccines are not recommended during pregnancy. For example, measles, mumps, and rubella vaccines should be avoided during pregnancy 打 唔 Any vaccine 打 Vaccine-preventable diseases cause long-term illness, can cause side effects hospitalization, and even death Vaccination Glossary o Immunity: Protection from an infectious disease. If you are immune to a disease, you can be exposed to it without becoming infected. o Immunization: A process by which a person becomes protected against a disease through vaccination. This term is often used interchangeably with vaccination or inoculation. o Vaccine: A preparation that is used to stimulate the body’s immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose. o Vaccination: The act of introducing a vaccine into the body to produce protection from a specific disease. (CDC US, 2024) Glossary o Antibody - A protein found in the blood, produced in response to foreign substances (e.g., bacteria or viruses) invading the body. Antibodies protect the body from disease by binding to invading organisms and destroying them. o Antigens - Foreign substances (e.g., bacteria or viruses) in the body that are capable of causing disease. The presence of antigens in the body triggers an immune response, usually the production of antibodies. o Antitoxin - A solution of antibodies against a toxin. Antitoxin can be derived from either human (e.g., tetanus immune globulin) or animal (usually equine) sources (e.g., diphtheria and botulism antitoxin). Antitoxins are used to confer passive immunity and for treatment. (CDC US, 2024) Type of Vaccines Inactivated vaccine (滅活疫苗) - A dead or inactivated form of a pathogen (killed by heat or formaldehyde) - Non-infectious if inactivating properly - Booster dose may be required (because the agents do not replicate in their hosts) Attenuated vaccine (減毒疫苗) - A weakened pathogen - The agents will replicate, booster dose may not be required - Risk of reversion of virulence (restored virulence) - Not suitable for immunocompromised individuals Subunit vaccine (次單元疫苗) - A portion of viruses or bacteria, e.g. protein or DNA molecules - Not infectious if processing properly - Often induce a weaker immune response - Also including toxoid vaccine (Vaccine Knowledge Project, 2021)  Vaccine Mechanism RNA Vaccines (mRNA Vaccine) - Basis of Pfizer How the Johnson & Johnson COVID-19 and Moderna COVID-19 vaccines, Animation vaccine works https://www.youtube.com/watch?v=VnJkPL-jlFI https://www.youtube.com/watch?v=oMXGGmBfkf8  Herd Immunity 群體免疫 o ‘Herd immunity’, 'community immunity' or 'herd protection' gives protection to vulnerable people such as newborn babies, elderly people and those who are too sick to be vaccinated. o high vaccination rate - it is difficult for infectious diseases to spread because there are not many people who can be infected. o Herd immunity does not protect against all vaccine-preventable diseases. The best example of this is tetanus, which is caught from bacteria in the environment, not from other people who have the disease. No matter how many people around you are vaccinated against tetanus, it will not protect you from tetanus. (WHO, 2020) Local Immunization Program  Hong Kong Childhood Immunization Programme 香港兒童免疫接種計劃 * 2018年7月1日或以後出生的兒童會於18個月大在母嬰健康院接種麻疹、流行性腮腺炎、德國麻疹及水痘混合疫苗。 2013年1月1日至2018年6月3 0日出生的兒童會於小學一年級接種麻疹、流行性腮腺炎、德國麻疹及水痘混合疫苗。 ^由2019/20學年起，合資格的女學童會於小學五年級接種「九價人類乳頭瘤病毒疫苗 – 第一次」，並於下一學年(小 六) 接種第二次 (FHS, 2020)  Hong Kong Childhood Immunization Programme 香港兒童免疫接種計劃 o Bacillus Calmette-Guérin (BCG) vaccine provides immunity against tuberculous meningitis in children o Hepatitis B vaccine provides immunity against hepatitis B virus o DTaP-IPV vaccine provides immunity against Diphtheria, Tetanus, acellular Pertussis & Inactivated Poliovirus Vaccine o Pneumococcal vaccine (PCV1315) provides immunity against Streptococcus pneumoniae o Attenuated mumps, measles, rubella, and varicella-zoster viruses (MMRV) vaccine provides immunity against measles, mumps, rubella, and varicella-zoster virus o Nine-valent human papillomavirus (HPV) vaccine reduces the risk of cervical cancer (FHS, 2020) Hong Kong Childhood Immunisation Programme (HKCIP) Human Papillomavirus (HPV) Vaccination 子宮頸癌疫苗接種 o The arrangement is implemented on the recommendations jointly made by the Scientific Committee on Vaccine Preventable Diseases (SCVPD) and the Scientific Committee on AIDS and Sexually Transmitted Infections (SCAS) under the CHP to incorporate HPV vaccine into the HKCIP. o What is HPV? HPV is the name of a group of viruses that includes more than 150 genotypes. Around 40 of these viruses infect the genital area. Some types of HPV can cause premalignant changes and malignant cancers of cervix, vagina, vulva and anus. o What is HPV vaccine? HPV vaccine is a prophylactic vaccine to prevent cervical cancer as well as other HPV-related cancers or diseases. In Hong Kong, HPV-16, 18, 31, 33, 45, 52, 58 accounted for about 90% of cases of cervical cancer. All the above seven genotypes are included in the 9-valent (九價) [strains] HPV vaccine. (CHP, 2024)  Government Vaccination Programmes (GVP) 2024-25 Replace 13-valent Pneumococcal Conjugate Vaccine With 15-valent Pneumococcal Conjugate Vaccine o Aim strengthening the immunity of children and the elderly against invasive pneumococcal disease (IPD) 侵入性肺炎球菌病. o IPD is caused by the bacteria Streptococcus pneumoniae (pneumococcus). o Streptococcus pneumoniae causes a wide range of diseases, more common ones include middle ear infection (acute otitis media) and chest infection (pneumonia). o It may also cause various forms of invasive pneumococcal diseases, such as infection of the brain membranes (meningitis) and blood stream (bacteraemia and sepsis). The infection can be serious or even life-threatening. (CHP, 2024)  Government Vaccination Programmes (GVP) 2024-25 Seasonal Influenza Vaccine (SIV) o quadrivalent influenza vaccine recommended by the Scientific Committee on Vaccine Preventable Diseases (SCVPD) for the 2024-25 season contain the following: an A/Victoria/4897/2022 (H1N1)pdm09-like virus 2A 2B an A/Thailand/8/2022 (H3N2)-like virus a B/Austria/1359417/2021(B/Victoria lineage)-like virus a B/Phuket/3073/2013(B/Yamagata lineage)-like virus o Recommended persons elderly aged 65 years or above as they pose a higher risk for complications, excess hospital admissions and deaths from influenza. Persons aged 50 to 64 are also recommended to receive SIV because local influenza epidemiology showed that people aged 50 to 64 years, irrespective of chronic medical problems, were having a higher risk of influenza-related intensive care unit admission and death Hight risk working group e,g healthcare workers (CHP, 2024) Health Care Workers in Hong Kong Pre-employment Immunization o Hepatitis B - HCW should be immune to hepatitis B and postvaccination serological status should be ascertained. Measurement of post-vaccination serological response for hepatitis B should be made at 1-4 months after the third dose to obtain the peak antibody levels. o Measles Rubella - HCW should be immune to measles and rubella, by either vaccination or medical evaluation. HCW without evidence of immunity Measles Rubella should be offered vaccination. Combined MMR vaccine is the preferred choice of vaccine as it confers protection against mumps as well o Chickenpox - HCW should be immune to varicella. HCW with negative or uncertain history of receiving two doses of varicella vaccines or disease of varicella or herpes zoster should be serologically tested. Vaccines should be offered to those without varicella zoster antibody. o Seasonal Influenza Vaccination - HCW should receive seasonal influenza vaccination annually once the vaccine is available (Scientific Committee on Vaccine Preventable Diseases, 2017) Decontamination Cleaning, Disinfection, Sterilization Cleaning and disinfection of environmental surfaces in the context of COVID-19 Interim guidance, WHO which status “In indoor spaces, routine application of disinfectants to environmental surfaces by spraying or fogging (also known as fumigation or misting) is not recommended for COVID-19” Army soldiers wearing protective suits spray disinfectant to prevent This photo taken on Feb. 18, 2020 shows members of a police sanitation team the spread of the new coronavirus at the Dongdaegu train station in spraying disinfectant on a bridge as a preventive measure agaist the spread of Daegu, South Korea, Saturday, Feb. 29, 2020. (Kim Hyun-tai/Yonhap the COVID-19 coronavirus in Bozhou, in China's eastern Anhui province. Photo via AP) by AFP (WHO, 2020) Decontamination Related Terms Disinfection a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects Sanitization Sanitizing reduces the number of germs on objects and surfaces to levels considered safe. Sterilization a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods, e.g. Steam under pressure, dry heat, EtO gas, hydrogen peroxide gas plasma, and liquid chemicals Decontamination a combination of processes that removes or destroys contamination so that infectious agents or other contaminants cannot reach a susceptible site in sufficient quantities to initiate infection, or other harmful response. (CDC US, 2024)  清 潔 (cleaning)及 消 毒 (disinfection) 清 潔 必 須 在 消 毒 前 進 行， 目的是清除污染物體表面的 先 清潔 有 機 物 (細 菌/ 病 毒 ) ，污 穢 / 塵 埃 後 消 毒 Remember C (cleaning ) comes BEFORE D (disinfection) (Rutala et al., 2024)  How do detergents work 皂分子 皂分子的疏水性部份 去除污垢和病原體 Soap Molecular 粘附著污垢 Removing Dirt & Pathogens Non-polar End of Soap Molecular is Attracted to the Dirt Polar Non-polar 親水 疏水性 污 垢 (疏 水 性) + 病 原 體 Dirty (Non-polar) Contaminated with pathogens (Soapnut Republic, 2021)  How Does Ultrasonic Cleaning Work? An ultrasonic cleaner is a machine that generates high-frequency sound waves to form tiny bubbles within a liquid solution; bubbles rapidly collapse or implode through a process known as cavitation, the machine helps dislodge dirt and tightly adhered contaminants from intricate items. https://www.youtube.com/watch?v=3OCr88B-mxA&t=126s Decreasing Order Resistance of Microorganisms To Disinfection & Sterilization Sterilization destroys all microorganisms on the surface of an article or in a fluid to prevent disease transmission associated with the use of that item – CDC USA (Rutala et al., 2024)  Spaulding Classification of Medical Devices “Spaulding” Classification of Medical Devices Decontamination Process Sterilization Critical pressurized steam, dry heat, gas (Ethylene oxide, Penetrates Skin or Mucous Membranes chlorine dioxide), hydrogen peroxide plasma, e.g. Surgical instruments, syringe vaporized hydrogen peroxide/peracetic acid, Ionizing needles Radiation completely eliminates or kill ALL microorganism Semi-Critical High Level Disinfection Touches Mucous Membranes Glutaraldehyde, Ortho-phthalaldehyde, Peracetic e.g. endoscopes, ventilator tubing Acid with hydrogen peroxide Kill vegetative bacteria but NOT all resistant spores Low Level Disinfection Non-Critical Touches Only Intact Skin; Environmental Alcohol, Chlorine, Quaternary ammonium Surfaces kill most vegetative bacteria and some fungi as e.g. stethoscopes, bed pans well as enveloped (lipid) viruses (e.g., hepatitis B virus, and HIV). (Rutala et al., 2024)  Use Biological Indicator (BI) ie Spores Test To Verify The Efficacy Of Certain Sterilization Processes Geobacillus stearothermophilus spores demonstrate a high resistance towards steam and vaporized hydrogen peroxide and are therefore used in BIs that Use-by date Date of manufacture Non-sterile Do not re-use monitor these sterilization processes. 3M™ Attest™ Super Rapid Readout Biological Indicator To indicate that the device is provided sterile and https://www.youtube.com/watch?v=y8i3InYaVMc has been sterilized using steam or dry heat. To indicate that the device is provided sterile and has been sterilized using irradiation To indicate that the device is provided sterile and has been sterilized using ethylene oxide Sterilizable in a steam sterilizer (autoclave) at temperature specified (PERÇİN, 2017) The End Click Here for reference list